One-pot synthesis of g-C3N4/MnO2 and g-C3N4/SnO2 hybrid nanocomposites for supercapacitor applications

Abstract

Carbon materials with layered structures with their unique surface area and charge transport properties have been attracting significant attention as electrode materials in renewable energy storage devices. The rapid agglomeration of layered materials during electrochemical processes reduces their shelf life and specific capacitance, which can be prevented by the introduction of suitable spacers between the layers. Herein, we report the electrochemical performance of MnO₂ and SnO₂ metal oxide spacers incorporated layered graphitic carbon nitride g-C₃N₄ in a symmetric two electrode configuration. The as-prepared g-C₃N₄/MnO₂ and g-C₃N₄/SnO₂ hybrid nanocomposites act as efficient electrode materials for symmetric supercapacitors. The performance of the electrode materials is compared with that of bare g-C₃N₄. A remarkable increase in specific capacitance was obtained for the g-C₃N₄/MnO₂ composite electrode (174 F g⁻¹) when compared to the bare g-C₃N₄ electrode (50 F g⁻¹) and g-C₃N₄/SnO₂ electrode (64 F g⁻¹). At a constant power density of 1 kW kg⁻¹ the symmetric supercapacitors based on g-C₃N₄, g-C₃N₄/SnO₂, and g-C₃N₄/MnO₂ electrodes exhibited energy densities of 6.9, 8.8 and 24.1 W h kg⁻¹ respectively.